### Single-Pane Window Heat Loss Equation and Calculator

**Heat Transfer Engineering**

**Thermodynamics**

**Engineering Physics **

Heat Loss through a Single-Pane Window Equation and Calculator

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Preview: Heat Loss Through a Single-Pane Window Calculator

Where:

Q = Heat Steady State Transfer (W)

A = Area (m^{2})

k = Thermal Conductivity (W/m · °C)

T_{∞1}
= Temperature (°C)

T_{∞2} = Temperature (°C)

h_{1} = Heat Transfer Coefficient (W/m^{2} · °C)

h_{2} = Heat Transfer Coefficient (W/m^{2} · °C)

R_{conv, 1} = Thermal Resistance (°C/W)

R_{conv, 2} = Thermal Resistance (°C/W)

R_{glass} = Thermal Resistance Glass (°C/W)

Example:

0.8-m-high and 1.5-m-wide glass window with a thickness of 8 mm
and a thermal conductivity of k = 0.78 W/m · °C. Determine the steady rate of
heat transfer through this glass window and the temperature of its inner surface
for a day during which the room is maintained at 20°C while the temperature of
the outdoors is -10°C. Take the heat transfer coefficients on the inner and
outer surfaces of the window to be h_{1} = 10 W/m^{2} · °C and h_{2} = 40 W/m^{2} · °C,
which includes the effects of radiation.

Assumptions

1 Heat transfer through the window is steady since the surface
temperatures remain constant at the specified values.

2 Heat transfer through
the wall is one-dimensional since any significant temperature gradients will exist
in the direction from the indoors to the outdoors.

3 Thermal conductivity is
constant.

all three resistances are in series, the total resistance is

steady rate of heat transfer through the window becomes

Knowing the rate of heat transfer, the inner surface temperature of the window glass can be determined from

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